Foursquare has just added a new notification setting to its check-in system called Always On. As you’d imagine from the title, it allows you to keep track of your friends check-ins at all times, no matter where they are.

The new notifications are not limited by geographic location, so you’ll get notifications even if they’re miles away or in a different part of the world. This is an interesting development that reminds me a lot of location services like Loopt.

Obviously, adding a real-time-ish component to friend tracking brings along a set of privacy issues. Apps like Banjo, Highlight, Glancee or Apple’s Find My Friends have run into these kinds of quandaries, and they handle them in different ways. Apple, for instance, offers a temporary allowance of tracking to users and the ability to ‘mute’ their awareness.

In order to turn the feature on, you visit a friend’s profile and toggle the option from nearby or off to ‘always on’.

To be clear, this doesn’t change anything about the way that Foursquare works (only friends can get these alerts, and they could see your activity anyway), but it does raise the awareness of your friend’s activity in the service’s profile. Foursquare no doubt hopes that this will encourage you to think of it as a living breathing service, rather than one that you use to ‘check in’ to things.

Founder Dennis Crowley has said that a key moment in the app’s history was when it figured out that Foursqare was being used to “look for where their friends are, to find things, and as a recommendation service,” adding, “It’s almost like it doesn’t occur to them to check in.”

It looks like they’re making attempts to fulfill those use cases with tweaks to the notification system.